Activity Diagram (beta)

So a completely new syntax and implementation is proposed as beta version to users (starting with V7947), so that
we could define a better format and syntax.
Another advantage of this new implementation is that it's done without the need of having
Graphviz installed (as for sequence diagrams).

The new syntax will replace the old one. However, for compatibility reason, the old syntax will still
be recognized, to ensure ascending compatibility.
Users are simply encouraged to migrate to the new syntax.

Notes

@startuml
start
:foo1;
note left: This is a note
:foo2;
note right
This note is on several
//lines// and can
contain <b>HTML</b>
====
* Calling the method ""foo()"" is prohibited
end note
stop
@enduml

Title & Legend

You can add title, header, footer, legend to a diagram:

@startuml
title this is my title
if (condition?) then (yes)
:yes;
else (no)
:no;
note right
this is a note
end note
endif
stop
legend
this is the legend
endlegend
footer dummy footer
header
this is
a long __dummy__ header
end header
@enduml

Colors

@startuml
start
:starting progress;
#HotPink:reading configuration files
These files should edited at this point!;
#AAAAAA:ending of the process;
@enduml

Arrows

Using the -> notation, you can add texts to arrow, and change
their color.

@startuml
:foo1;
-> You can put text on arrows;
if (test) then
-[#blue]->
:foo2;
-[#green]-> The text can
also be on several lines
and **very** long...;
:foo3;
else
-[#black]->
:foo4;
endif
-[#gray]->
:foo5;
@enduml